Disposable lancet

ABSTRACT

A disposable lancet used for piercing the tissue of a finger to obtain blood specimens. The lancet is designed to contain minimum material to achieve low material costs which still have the strength and rigidity to be completely functional. The lancet design permits multiple lancets to be punched from a strip of sheet steel to obtain economy in the manufacturing operation.

United States Patent [1 1 Malmstrom Feb. 5, 1974 DISPOSABLE LANCET [75] Inventor: Sven-Erik Malmstrom, Reftele,

Sweden [73] Assignee: Swedish Hospital Supply SHS AB,

Malndal, Sweden [22] Filed: Sept. 22, 1971 [21] Appl. No.: 182,862

[52] US. Cl 128/2 F, 128/314 [51] Int. Cl. A61b 10/00, A6lb 17/32 [58] Field of Search 128/2 F, 314

[56] References Cited UNITED STATES PATENTS 3,060,937 10/1962 Griffitts et al. 128/314 3,517,670 6/1970 Speelman 128/314 Primary Examiner-Channing L. Pace Attorney, Agent, or FirmAlbert L. Jeffers; Roger M. Rickert [57] ABSTRACT A disposable lancet used for piercing the tissue of a finger to obtain blood specimens. The lancet is designed to contain minimum material to achieve low material costs which still have the strength and rigidity to be completely functional. The lancet design permits multiple lancets to be punched from a strip of sheet steel to obtain economy in the manufacturing operation.

4 Claims, 2 Drawing Figures DISPOSABLE LANCET BACKGROUND OF THE INVENTION The invention described herein relates to surgical instruments and more particularly to a lancet used for collecting small amounts of blood for test purposes.

A lancet is a surgical instrument having a sharp pointed end used for piercing the tissue of a patients finger to obtain blood specimens. It is manufactured from stainless steel and comprises a piercing portion having a sharp point which merges into a shoulder of substantially greater width which restricts the penetration depth of the lancet. The shoulder is integrally formed with a relatively long handle or grip portion having an outer end (pressure surface) against which a persons thumb is placed for pushing the pointed end of the lancet into the tissue of a finger.

Conventional lancets of this kind have a handle or grip portion of uniform width, and the handle width is determined more with regard to the required size of the pressure surface and the shoulder than with regard to the required stiffness of the lancet.

As a result, the handle includes substantially more material than is necessary for the lancet to perform its intended function. It has been estimated that the cost for materials in a lancet constitutes more than 40 percent of the lancet sales price and it therefore is obvious that reduction in the amount of material used will be reflected in reduced costs to the purchaser. Also, for both medical and economic reasons, a lancet is used only once and then discarded and this fact accordingly dictates that the lancet must be designed to achieve acceptable performance at the lowest manufacturing and material costs.

The present invention reduces the material and manufacturing costs for a lancet by about 50 percent. This reduction is obtained by the fact that the shoulder is connected with the handle by means of a neck portion having reduced width in relation to the shoulder and that the width of the handle increases from the width of the neck portion at the connection thereto in the direction of the free end of the handle. Another feature is that the handle is provided with recesses which are of the same size and shape as the shoulder portion or sections thereof. For example, the shoulder portion comprises two sections symmetrically positioned or only one section positioned at one side of the lancet.

To obtain economy in the manufacturing process, lancets preferably are stamped from strips having substantially the same width as the entire length of each lancet, one lancet being positioned in one direction and the adjacent lancets being positioned in the opposite direction, the sections of the shoulder of one lancet being formed by corresponding recesses in the adjacent lancets.

SUMMARY OF THE INVENTION Briefly stated, the above disadvantages of the prior art are eliminated by providing a disposable lancet which contains the minimum amount of material necessary to impart strength and rigidity to the lancet structure while still permitting the lancet to perform its intended function at an optimum performance level. To achieve manufacture of a lancet at minimum costs, a manufacturing process is used wherein a strip of sheet steel is moved cyclically into a punch press and multiple lancets simultaneously are stamped or punched from the steel strip.

An object of the invention is to provide a highly functional lancet capable of being manufactured at low cost; and

Another object of the invention is the provision of an improved manufacturing process which stamps or punches multiple lancets from strips of sheet steel.

BRIEF DESCRIPTION OF THE DRAWING While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter of the'invention, it is believed the invention will be better understood from the following description taken in conjunction with the accompanying drawing, wherein:

FIG. 1 is a plan view of a steel strip illustrating multiple lancets punched therefrom during a manufacturing operation; and

FIG. 2 shows a plan view of a modification of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing wherein like reference characters designate like or corresponding parts, there is shown in FIG. 1 a strip 10 of stainless steel or other material preferably having a thickness of 0.15 to 0.20 mm and of a length sufficient to stamp out multiple lancets during the manufacturing operation. The plan view of FIG. 1 shows the configuration of each lancet 11 as the manufacturing proceeds. To acquire perspective on the size, the lancets of FIG. 1 are shown magnified about 5 times the actual size of a lancet used for blood specimen purposes.

Each lancet 11 is provided with a piercing portion having a sharp point 12 which enters the tissue of a patients finger when the lancet is being used. The piercing portion uniformly increases in width from point 12 and merges in a shoulder 13 having two reversed sections 13a and 13b of the same shape symmetrically positioned with respect to the longitudinal axis of the lancet. The function of the shoulders is to restrict the distance that the piercing portion may be inserted in a finger and the piercing portion length may obviously-vary depending on lancet use.

The shoulder 13 is of substantially the same shape as an equilateral triangle, one point of the triangle being directed opposite to the point 12 and which merges into a grip portion or handle 14. As shown, the handle 14 increases in width in the direction of the handle free end 15 which is rounded to provide a pressure surface or area 16 against which a persons finger may be placed for pushing the lancet point 12 into a patients finger. The handle is provided with recesses 17a and 17b to help minimize the amount of material used. A longitudinal depression 18 extends from the free end along the handle length to the piercing portion for imparting strength and rigidity to the lancet.

The lancet is preferably manufactured by a stamping or punching operation. Referring to FIG. 1, as the stainless steel strip 10 is fed into a machine having a die shaped to the configuration of a lancet, and the machine cycled for a first stamping operation, the lancet 1 la is first stamped out. The previously stamped lancet 1 1 is then detached from the strip although in the usual operation, the cut will be clean and the lancet will fall into a collecting bin.

As the strip steel is fed into the machine for the next cut and again cycled, the lancet 1 1d is stamped out and the lancet 1 1c detached, and so on, until the strip is exhausted. It will be noted that two lancets are formed by each stamping operation, thus doubling the speed of production over prior methods. Further, the design of the lancet has been chosen to utilize to the maximum extent, all the material in the steel strip. Reference to FIG. 1 shows that the only material wastage is that small amount between the pressure surface 16 and the edge of the strip.

Consideration of the lancet design and the manufacturing process used in forming the lancet shows that substantial savings in material over prior art designs has been achieved. This saving coupled with doubling the lancet production speed has resulted in an overall cost reduction of approximately 50 percent.

In the embodiment of FIG. 1, the lancets are stamped from strips having substantially the same width as the entire length of each lancet, one lancet being positioned in one direction and the adjacent lancet being positioned in the opposite direction, with the sections of the shoulder of one lancet being formed by the corresponding recesses in the adjacent lancets.

In the modification of FIG. 2, the lancets are manufactured by being stamped from strips having substantially the same width as the maximum width of the grip portion or handle, one lancet being positioned in one direction and the adjacent lancet being positioned in the opposite direction, and the shoulder of each lancet being formed by a corresponding recess in the handle of the adjacent lancet.

In FIG. 2, two lancets 21a and 21b are stamped from the strip in a single operation. As is evident, the width of the strip equals the greatest width of each of the lancets.

Each lancet comprises a piercing portion 22 which merges into a single shoulder 23 asymmetrically positioned on one side of the lancet. The shoulder 23, which is substantially triangular in shape, continues into the grip portion or handle 24 of the lancet. The width of the handle increases in the direction of the free end 25 and is rounded to provide a pressure surface 26. A recess 27 having the same configuration as the shoulder 23 is formed in the free end 25 of the handle. As in the preferred embodiment, the strip 20 is provided with two stiffening depressions 28 to impart strength and rigidity to the lancet.

I In the manufacturing operation, the section 3011 is first separated from the strip to form the pressure surface 26 on the lancet 21a. The strip 20 is fed forward along the length of one lancet and is cut at 31 to separate the two lancets 21a and 21b from each other. The section 30b is then stamped out either during the same operation when cut 31 is made or in a separate operation. Upon separation of the two lancets, each will be provided with sharp points 22 as a result of cutting along the length and into the edge of the strip material.

In view of the above, it will be apparent that many modifications and variations are possible in light of the above teachings. It therefore is to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.

What I claim as new and desire to secure by United States Letters Patent is:

1. A blood-letting lancet constructed from sheet metal comprising, a grip portion of a generally elongated shape, a piercing portion disposed at one end of the lancet provided with a sharp point, a lateral recess formed in the grip portion adjacent the end thereof opposite said pointed end a penetration limiting portion disposed between the grip portion and the piercing portion and integral therewith for restricting the penetration depth of the piercing portion, said penetration lim iting portion having a substantially greater width than the adjacent grip portion, said penetration limiting portion being defined by at least one lateral projection having the same configuration as the lateral recess formed in the grip portion.

2. The combination according to claim 1 wherein said grip portion includes recesses on opposite sides of the grip portion axis which are complementary to the configuration of said penetration limiting portion.

3. The combination according to claim 1 wherein said penetration limiting portion comprises a pair of sections projecting respectively, transversely from the longitudinal axis of said grip portion and are symmetrically disposed relative to said axis, and said sections each having an edge on the piercing portion side of said penetration limiting portion which lies perpendicular to said axis for limiting the depth of penetration of said piercing portion.

4. The combination according to claim 1 wherein said penetration limiting portion is asymmetrically po- 

1. A blood-letting lancet constructed from sheet metal comprising, a grip portion of a generally elongated shape, a piercing portion disposed at one end of the lancet provided with a sharp point, a lateral recess formed in the grip portion adjacent the end thereof opposite said pointed end a penetration limiting portion disposed between the grip portion and the piercing portion and integral therewith for restricting the penetration depth of the piercing portion, said penetration limiting portion having a substantially greater width than the adjacent grip portion, said penetration limiting portion being defined by at least one lateral projection having the same configuration as the lateral recess formed in the grip portion.
 2. The combination according to claim 1 wherein said grip portion includes recesses on opposite sides of the grip portion axis which are complementary to the configuration of said penetration limiting portion.
 3. The combination according to claim 1 wherein said penetration limiting portion comprises a pair of sections projecting respectively, transversely from the longitudinal axis of said grip portion and are symmetrically disposed relative to said axis, and saId sections each having an edge on the piercing portion side of said penetration limiting portion which lies perpendicular to said axis for limiting the depth of penetration of said piercing portion.
 4. The combination according to claim 1 wherein said penetration limiting portion is asymmetrically positioned on one side of said strip. 